Insulated steel sheeting is very common here for industrial buildings, they do up to 250mm thick I believe, you can get 1m wide or 2 m wide sheets by whatever length you need, 6m long seems to be the most the cladders want to mess with, it gets real heavy, the 2m wide stuff is mostly for roofs and you need a crane to put it on.
We did a 10,000 sq foot building with 100mm on the roof and 80mm walls, the sheeting was 3/4 of the total cost of the supply and erect of the building from the building supplier, its like 2 or 3 hundred £ a sheet where plain painted steel would be £20
Makes a nice building though and you don't have to mess with adding any insulation or framing to hold the insulation.
You can get your standard box profile, fake roman style tile surface, fake slate surface, a standing seam system and many others, in loads of colours, with 12 point plastic capped screws to match.